2l8 



BOTANICAL GAZETTE 



[APRIL 



spending reading \\3.s made of the standard vaporimeter, as nearly 

 simultaneously as possible (fig. i) . 



The vaporimeter consists of a porous cup supported about 



above a pint jar by a glass tube which extends from the upper end of 



Fig. I. 



porous 



positions 



Contour 



tube is fitted air tight 



porous cup by a rubber stopper. The top of the jar is covered 



by a cork wUch is nearly air tight 

 jar is a conical shield of paraffined do 

 jar was sunk in the ground to within 



abov 

 In 



In 



